The present invention relates to a method of manufacturing a semiconductor device and particularly, to the method employing a film carrier tape during process steps thereof.
The film carrier tape for semiconductor chips is widely used in manufacture of semiconductor devices, in which a plurality of bonding pads of each semiconductor chip (semiconductor element) are simultaneously bonded to a plurality of leads formed on the film carrier tape of a plastic material such as polyimide.
The prior art film carrier tape has a plurality of test pads thereon which are connected to respective leads. After the bonding of the bonding pads to the leads are completed, electrical tests are conducted by contacting probes of a test apparatus to the test pads on the film carrier tape to evaluate the characteristics of the semiconductor element as well as the bonding conditions. Also, a bias test is conducted by applying power voltages such as Vcc, Vss or ground to the corresponding test pads for 4 to 24 hours at a temperature of 100.degree. C. to 150.degree. C.
It is a recent trend that the number of bonding pads on the semiconductor element is remarkably increased due to the enhancement of the circuit integration density in the semiconductor element. The increase in the number of the bonding pads brings about an increase in the number of the leads on the film carrier tape and as a result, a large number of test pads must be formed on the film carrier tape. In order that an increased number of the test pads may be provided in the limited space of the carrier tape, an area of each test pad must be reduced. However, the size of each test pad cannot be made less than 1.5 mm.times.1.5 mm square to maintain accurate contact with the probes of the test apparatus in view of the deformation of the carrier tape under the environment of the high temperature in the bias test and the tolerance of the alignment between the test pads and the test probe or test electrodes.
To solve the problem, the space of the carrier tape for the test pads must be enlarged. This may be done by either increasing a unit length of the carrier tape assigned to each semiconductor element or expanding the width of the tape. However, the former method increases a length of the lead from the bonding pad of the semiconductor element to the test pad, resulting in an increase in the electric resistance of the lead thereby to exert unfavorable influences upon the test. According to the latter method, on the other hand, the test apparatus or the fabricating apparatus have to be remade to have the standards suited for a new tape width. Because the usual width of the film carrier tape is 35 mm which is the same as the width of a movie film.
Further, the increase in the power consumption of the semiconductor element makes it necessary to adopt counter-measures for the heat dissipation in the semiconductor element. It is, however, very difficult to add radiating plates or fins to the film carrier tape for heat dissipation, thus raising still another problem that the influences of heat generation in the test or the like cannot be avoided.